This is a Phase II/lll study to evaluate the effects of exisulind for treatment on duodenal adenomatous polyps and on adenoma and mucosal apoptosis assays in Familial Adenomatous Polyposis (FAP) patients who have had colectomy or Attenuated Adenomatous Polyposis Coli (AAPC) patients whom may or may not have undergone colectomy. These subjects have a defined high genetic risk of developing duodenal cancer (relative risk 300). This is a double blind, placebo controlled, single center study. One hundred subjects, fifty each arm, will be enrolled. Eligible subjects who harbor 10 to 40 duodenal polyps within a measured segment are randomized to receive exisulind 150 mg p.o. qid or an identical placebo for the duration of one year. (Persons with AAPC whom still have colon intact will receive 200 mg bid for the same duration. Gastroduodenoscopy will be performed at baseline to assess polyp status and place, where applicable, a tattoo 10 cm beyond the papilla of Vater. Duodenal polyps are mapped for number and size at baseline and at follow up at year one. Polyp and mucosal biopsies will be obtained for apoptosis. Subjects are contacted bi-monthly for assessments. Drug is dispensed every three months and a pill count is recorded monthly. Chemistries, CBC and urinalysis is performed at baseline and at 1, 3, 6 and 12 months. A beta-HCG is performed initially on all fertile women. The NCI common toxicity criteria is employed to detect toxicities and an external Data Safety Monitoring Committee serves to review all adverse events and any protocol issues. A 5-year study is proposed. The randomized treatment period is 1 year. There will be a 6 month termination phase to include data analysis, manuscript preparation and closure of all study procedures. [unreadable] [unreadable]